EVERYDAY SCIENCE

Detailed explanation-1: -So the dominant allele is always expressed, but it can differ in penetrance and is therefore not always as clearly expressed in the cell’s phenotype as you expect from a dominant allele.

Detailed explanation-2: -A dominant allele produces a dominant phenotype in individuals who have one copy of the allele, which can come from just one parent. For a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent.

Detailed explanation-3: -A dominant trait will always be expressed in the offspring if the dominant allele is present, even if there is only one copy of it (heterozygous or dominant homozygous, Aa or AA).

Detailed explanation-4: -Alleles that exhibit complete dominance will always be expressed in the the cell’s phenotype. However, sometimes dominance of an allele is incomplete. In that that case, if a cell has one dominant and one recessive allele (i.e. heterozygous), the cell can display intermediate phenotypes.

Detailed explanation-5: -A genotype is always expressed in the phenotype.